Weather roof for floating tank roofs



J. H. WIGGINS WEATHER ROOF FOR FLOATING TANK 'ROOFS Filed July 9, 1952 FIG.|.

Sept. 27, 1955 INVENTOR, J0 N H. W? BY jz ATTORNEY United States Patent Ofifice 2,718,977 Patented Sept. 27, 1955 2,718,977 WEATHER ROOF FOR FLOATING TANK ROOFS John H. Wiggins, Chicago, Ill.

Application July 9, 1952, Serial No. 297,930

2 Claims. (Cl. 220--26) This invention relates to a weather roof of novel construction that is adapted to be used with various kinds and types of floating tank roots.

The main object of my invention is to provide a stationary weather roof for a liquid storage tank equipped with a floating roof, which is of such design or construction that (a) it insures sufficient ventilation for the space between the weather roof and the floating roof to make it impossible for an explosive mixture to exist in said space, and (b) it eliminates the possibility of any rain that may be blown into the space between the two roofs through a ventilating opening, from reaching the inner face of the tank side wall and eventually finding its way into the tank through the joint between the tank side wall and the peripheral sealing mechanism of the floating roof.

Figure 1 of the drawings is a vertical transverse sectional view, illustrating a floating tank roof equipped with a weather roof embodying my invention, and

Figure 2 is a top plan view of the structure shown in Figure 1.

In the drawings the reference character 1 designates the side wall of a liquid storage tank and 2 designates the bottom of the tank. Said tank is equipped with a floating roof that may be of any preferred type or design but which is herein illustrated as a modified pan type floating roof provided with a deck 3, an annular rim 4 located at the peripheral edge of said deck, and a conventional peripheral sealing mechanism that comprises an annular shoe 5 arranged in a sliding engagement with the tank side wall and a flexible gastight sealing element 5 attached to said shoe 4 and to the rim 4 of the floating roof.

My invention consists of a stationary weather roof 7 mounted on the tank and constructed and arranged so as to produce a ventilating opening A of relatively great a diameter located at the center of said weather roof and an annular ventilating slot B located between the peripheral portion of said weather roof and the top edge of the side wall 1 of the tank. The weather roof 7 may be of any preferred shape or construction and it can be mounted in any preferred way on the tank side wall. It is herein illustrated as being substantially dome shape and provided at its periphery with an annular member 6 of angle shape in cross section that is rigidly attached to the tank side wall by lugs 13 of such shape and arrangement that the horizontal leg of the member 6 is maintained in spaced relation with the top edge of the tank side wall and the vertical leg of said member 6 surrounds and is maintained in spaced relation with the tank side wall, thereby producing the previously mentioned ventilating slot B between the tank side and the peripheral portion of the weather roof. The ventilating opening A at the center of the weather roof is preferably formed by an open ended tubular or cylindrical structure, mounted in the roof 7 in such a way that the major portion of the length of said structure will project downwardly a considerable distance below said roof and hence will function as a baflie that effectively prevents rain that blows downwardly through the center ventilating opening A of the weather roof from coming in contact with the inner surface of the tank side wall 1 as hereinafter described. Said tubular structure may consist of a cylinder of considerably greater diameter than length, rigidly mounted on the weather roof in such a position that its lower end is in close proximity to the floating roof when said floating roof is in its highest or uppermost position, or it may consist of a cylinder rigidly attached to the weather roof and provided with a telescoped or extensible and contractible lower end portion that folds and unfolds during the rise and fall of the floating roof.

In the form of my invention herein illustrated, the tubular or cylindrical structure that forms the center ventilating opening of the weather roof, is composed of an open ended, rigid rain and wind deflecting cylinder 9 attached to the weather roof 7 with its upper end projecting slightly above the top surface of said roof, and a collapsible cylinder 10; made of fabric, suspended from the lower end of said deflecting cylinder 9 by a supporting member 11, formed by a rod bent into circular form, and attached to lugs 14 that project inwardly from the lower end portion of the rigid cylinder 9, said supporting member 11 and lugs 14 being so constructed and arranged as to produce a ventilating slot at the lower end of the rain and wind deflecting cylinder 9 up through which air circulates as indicated by the arrow 18 at the left hand side of Figure l. The collapsible fabric cylinder 10 has a bottom ring 12 attached to its lower end so as to impose a downward load on said fabric cylinder which tends to hold it in a distended condition in certain positions of the roof. As the floating roof rises from its lowermost position, lugs 15 on the deck 3 of the floating roof come into contact with the bottom ring 12 of the fabric cylinder 10 as shown in broken lines and thus cause said cylinder 10 to collapse or fold as shown in solid lines in Figure 1, said lugs 15 causing the bottom ring 12 of the fabric cylinder to be held in spaced relation with the deck of the floating roof and thus produce a ventilating slot through which air can enter the lower end of the collapsible fabric cylinder 10 and thence flow upwardly through same and through the rigid cylindrical member 9 at the center of the weather roof. The member 9 in addition to functioning as a rain and wind deflector, also serves as the central portion of a frame work for the weather roof 7 that comprises radially disposed ribs or beams 8 attached at their inner ends to the central member 9 and attached at their outer ends to the peripheral member 6 of the roof.

In order to effectively prevent rain from being blown into the space between the floating roof and weather roof, through the annular ventilating slot B between the weather roof and the tank side wall, I prefer to attach a fabric curtain 20 to the vertical leg of the peripheral member 6 of the weather roof as shown at the right hand side of Figure 1. Said curtain 20 extends around the entire circumference of the weather roof, but it has been omitted from the left hand side of Figure l in order to illustrate the overflow 16 in the tank side wall that controls the maximum height to which the floating roof can rise in the tank. The curtain 20 can either be constructed in the form of a continuous annular member or it can be composed of a plurality of segmental sections that are capable of swinging relatively to each other. When wind blows hard, for example from the right hand side of the tank the curtain 20 flexes or swings into the position indicated by the dotted line in Figure 1, thereby effectively closing the peripheral venting slot B and preventing rain from being carried through said slot into the space between the floating roof and the weather roof.

The weather roof 7 covers a large portion of the total tank area but there is a ventilating opening A of relatively great diameter at the center of the roof that insures eflicient ventilation of the space between the floating roof and weather roof andalsoreduces the:quantity.of.steel used in 'the construction .of the weather roof. .Even though said center ventilating opening is .ofrelatively great diameter. rain that .blowsdownwardly through same will not come incontact with .the innensurfaceaof 'the tank side wall and:eventually find. its way intotheZIiquid storage space ofthetank dueito. the factfthat said center ventilating opening is formed by a tubular orcylindrical structure that functionsias vfollows: .(a) It'causes wind blowing over thetopside-of thereof 7 .in the direction indicated by theharrow 17, to createapartial .vacuum over .the windward half-of the.opening A, and (b) it directs the wind that hitsthe leeward sideof thecylinder 9 downwardly as. indicated by the arrows 19 in-Figure 1, thereby causing any rain drops .carried by such wind to be deflected downwardly insubstantially a straightline as shown in Figure 1. 'If the .tank side wall is relatively low compared toits diameter, a cylindrical, rigid member 9 mounted inthecentralportionof the weather roof 7 will deflect downwardly any wind .currents'that blow downwardly through the center =ventilating opening A, but if the tankside wall is very high compared to its diameter it is necessaryto equip the Weather roof with a central wind and air deflector provided with. a collapsible or telescoping lower endportion 10 so as to increase the deflecting effect of the tubular or cylindrical member 9 mounted in the roof, said members 9 and 10 being preferably of such construction that there is a ventilating slot or spacebetween said members at the point where they are joined together and also between the lower-end of the member '10 and the deck of the floating roof as previously explained.

In order to prevent rain from being blown inwardly through the ventilating slot Bbetween the Weather roof and the tank side wall under high wind conditions, I prefer to attach a flexible-or swinging curtain or rain shield 20 to the peripheral portion of the weather roof as previously explained. When a hard wind is blowing from the right (looking at'Figure l) the shield 20 will flex or swing into the dottedline position so as to close the ventilating slot B on the windward side and prevent rain from blowing inwardly through said slot.

With a proper peripheral seal on the floating roof. and for liquids that do not boil at the temperatureto which they are subjected during storage, a .weatherroof .constructed in accordance with my invention providesmore than ample circulationof airbetween the floating roof and the weather roof, without liability of .rain, even a driving rain, coming in contact with the tank side wall and eventually finding its way-into the tank by leaking through the sealing mechanism at the periphery .of the floating roof which acts on the'in'ner face of the tank side wall. Also as previously explained by equipping the weather roof with a centrally located, open ended tubular structure of relatively great diameter that efiectively "4 ventilates the space between the weather roof and floating roof without liability of'the 'liqui'd stored in the tank becoming contaminated by rain Water, I reduce the quantity of steel used in the weather roof and hence reduce the cost of same.

Having thus described my invention, what I claim and desire to secure by Letters Patent is:

l. The combination of' a l'iquid storage tank provided with :acylindrical side wall, a floating roof in said tank, a stationary weather roof of greater diameter than said tank mounted ontthe upper erid of same with the under side of -said-weatherv roof spaced-away from the top edge of the tank side wall so as to form an annular ventilating slot that extends around the rentiret'circumference of the tank, a depending flange on the periphery of said weather root extending downwardly from same to a point below the top edge of the tank side Wall and spaced away from same so as to form a bafllethatipreventsrain from blowing inwardly through saidannularventilatingslot, astationary, vertically disposed-openien'ded tubular member of relatively: great.diametermountedin said weatherroof with the lower -end .of.said tubular member terminating at a point a substantial distance belowthe underside/of said weather'roof, and-acontractible and .extensibletubular structuresuspended from the'lowerend of sai'd stationary tubularmernber so as to formian extensionot same that is adapted to'be engaged by the floating-roof when the liquid in the tank iseabove acertain approximate level, the-uppenend of-said -contractible and-extensible structure being spaced away vfrom the lower end of said stationary tubular member anddisposed in telescoped relationship with samesoasto forman annular ventilating slot for the space between the floating roof and stationary roof when said extensionuis.inengagement with the floating roof.

2. A structure-of'the kind described in claim 1, which also includes-ameansicarried bythe peripheral flange of the stationary roof for preventing rain from blowinginwardlythrough thetannular yentilatin-g slot between said roof-rand the tank -sidewall,.anda meansfonproducing a ventilating opening between=the floatingroofand the lower end of theex-tension-ofthe tubular-membenon the stationary roof -when said extension is.in-.en gagement with the floating roof.

References .Cite'dinthefile of this,patent UNITED lST'A'FES PATENTS 469,356 "Kelly Feb. 23, '18'92 1,463,268 Htlif July-31, 1923 1,521,555 Huff Dec. 30, 1924 1;61l,440 Haupt "Dec. 21,1926 2,125,771 "Detiastro Aug. '2, 1938 2,541,090 Orr'et al. Feb. 1 3, i951 FOREIGN PATENTS 648,537 Germany Aug. 3, 1937 

